TEAS 7 Science Study Guide
The TEAS Science section tests your knowledge of basic science concepts that nurses need to understand.
This section has 50 questions and you get 60 minutes to complete it. You’ll need to know anatomy, physiology, biology, chemistry, and scientific reasoning.
This guide covers everything you need to know for the science section. Each topic includes clear explanations, real-world examples, and practice questions.
The science section is often considered the hardest part of the TEAS exam, but with good preparation, you can succeed.
The science section focuses heavily on how the human body works. You’ll also need to understand basic chemistry, cell biology, and how to think like a scientist. Most questions connect to healthcare situations you’ll face as a nurse.
Overview of the Science Section
What You Need to Know
The Science section contains 50 total questions. Only 44 questions count toward your score. The other 6 questions are unscored test questions that don’t affect your grade.
You have 60 minutes to complete this section. That gives you about 1 minute and 12 seconds per question. Some questions require more thinking time, while others you can answer quickly.
The questions test different types of knowledge. Some ask you to recall facts about body systems. Others require you to apply scientific principles to new situations. A few questions ask you to interpret graphs or analyze experimental data.
Content Distribution
Human Anatomy and Physiology makes up the largest portion with 18 questions. This covers all the major body systems and how they work together. Biology has 9 questions focusing on cells, genetics, and microorganisms.
Chemistry has 8 questions about atoms, molecules, and chemical reactions in the body. Scientific Reasoning has 9 questions about the scientific method, measurements, and data analysis.
Most questions connect science concepts to healthcare situations. You might see questions about what happens during a heart attack, how medications work in the body, or why certain lab values are abnormal.
Types of Questions You’ll See
Multiple choice questions are most common, with four answer options. Some questions ask you to select all correct answers from a list. A few questions require you to type in a numerical answer or click on parts of a diagram.
Hot spot questions show you a diagram and ask you to click on the correct structure. Order response questions ask you to put steps in the correct sequence, like the stages of cell division or steps in the scientific method.
All questions test your understanding of science concepts, not just memorization. You’ll need to apply what you know to solve problems and analyze situations.
Human Anatomy and Physiology
This section covers how the human body is built and how it works. You need to understand the major body systems and how they interact with each other. These concepts are essential for nursing practice.
The human body is amazingly complex, but it follows logical patterns. Each system has specific functions, but all systems work together to maintain health.
Understanding normal body function helps you recognize when something goes wrong.
General Anatomical Orientation
The body has a standard reference position called anatomical position. In this position, the person stands upright, facing forward, with arms at the sides and palms facing forward. All directional terms are based on this position.
Directional terms help describe where body parts are located. Superior means toward the head, while inferior means toward the feet.
Anterior means toward the front, while posterior means toward the back. Medial means toward the middle of the body, while lateral means away from the middle.
The body can be divided by imaginary planes. The sagittal plane divides the body into left and right parts. The frontal plane divides it into front and back parts. The transverse plane divides it into upper and lower parts.
Practice Question:
The heart is located _______ to the lungs and _______ to the spine.
A) Medial, anterior
B) Lateral, posterior
C) Superior, medial
D) Inferior, lateral
Answer: A) Medial, anterior
Explanation: The heart is closer to the midline of the body than the lungs (medial), and it’s closer to the front of the body than the spine (anterior). This demonstrates how directional terms help locate body structures precisely.
Skeletal System
Bones provide structure and support for the body. They also protect internal organs, store minerals like calcium, and produce blood cells in the bone marrow. The adult human body has 206 bones.
Bones are living tissues that constantly break down and rebuild. This process is called remodeling. When you break a bone, new bone tissue grows to repair the damage. Exercise and good nutrition help keep bones strong.
Joints are where two or more bones meet. Some joints, like those in the skull, don’t move. Others, like the knee and elbow, allow extensive movement. Cartilage covers the ends of bones at moveable joints to reduce friction.
The skeleton has two main parts. The axial skeleton includes the skull, spine, and rib cage. It protects the central nervous system and internal organs.
The appendicular skeleton includes the arms, legs, and the bones that attach them to the axial skeleton.
Practice Question:
Which of the following is a function of the skeletal system?
A) Producing hormones
B) Filtering blood
C) Storing minerals
D) Digesting food
Answer: C) Storing minerals
Explanation: Bones store important minerals, especially calcium and phosphorus. While other body systems produce hormones, filter blood, and digest food, mineral storage is a key function of the skeletal system.
Muscular System
Muscles create movement by contracting and relaxing. The body has three types of muscle tissue. Skeletal muscle is attached to bones and creates voluntary movement.
Cardiac muscle makes up the heart and pumps blood. Smooth muscle is found in internal organs and blood vessels.
Skeletal muscles work in pairs. When one muscle contracts, its partner relaxes. For example, when your bicep contracts to bend your elbow, your tricep relaxes. When you straighten your elbow, the tricep contracts and the bicep relaxes.
Muscles need energy to contract. They get this energy from glucose and oxygen delivered by the blood. During intense exercise, muscles can work without oxygen for short periods, but this creates lactic acid that causes fatigue and soreness.
Regular exercise makes muscles stronger and more efficient. Unused muscles become weak and may shrink in size. This is why physical therapy is important for patients who are bedridden or have limited mobility.
Practice Question:
What happens to the tricep muscle when the bicep contracts to flex the elbow?
A) The tricep also contracts
B) The tricep relaxes
C) The tricep stays the same
D) The tricep stretches
Answer: B) The tricep relaxes
Explanation: Muscles work in opposing pairs. When the bicep contracts to bend the elbow, the tricep must relax to allow this movement. This coordinated action prevents muscles from fighting against each other.
Nervous System
The nervous system controls and coordinates all body activities. It receives information from the environment, processes that information, and responds appropriately. The nervous system works faster than any other control system in the body.
The central nervous system includes the brain and spinal cord. The brain processes information and makes decisions.
The spinal cord carries messages between the brain and the rest of the body. The peripheral nervous system includes all nerves outside the brain and spinal cord.
Neurons are the basic cells of the nervous system. They receive signals, process them, and send signals to other neurons or to muscles and glands.
Signals travel as electrical impulses along the neuron, then jump to the next neuron using chemical messengers called neurotransmitters.
Reflexes are automatic responses that don’t require conscious thought. When you touch something hot, you pull your hand away before you even realize it’s hot. This reflex protects you from injury by responding faster than conscious thought.
Practice Question:
Which part of the nervous system carries messages between the brain and the rest of the body?
A) Neurons
B) Spinal cord
C) Peripheral nerves
D) Neurotransmitters
Answer: B) Spinal cord
Explanation: The spinal cord is the main pathway for communication between the brain and the peripheral nervous system. It carries sensory information to the brain and motor commands from the brain to muscles and organs.
Cardiovascular System
The cardiovascular system delivers oxygen and nutrients to every cell in the body. It also removes waste products and helps regulate body temperature. The system includes the heart, blood vessels, and blood.
The heart is a muscular pump with four chambers. The right side pumps blood to the lungs to pick up oxygen. The left side pumps oxygen-rich blood to the rest of the body. Heart valves ensure blood flows in the correct direction.
Blood vessels form a network throughout the body. Arteries carry blood away from the heart under high pressure. Veins return blood to the heart under low pressure. Capillaries are tiny vessels where oxygen and nutrients move between blood and tissues.
Blood pressure measures the force of blood against artery walls. The top number (systolic) is pressure when the heart contracts. The bottom number (diastolic) is pressure when the heart relaxes. Normal blood pressure is less than 120/80.
Practice Question:
What is the main function of capillaries?
A) Carry blood away from the heart
B) Return blood to the heart
C) Exchange materials between blood and tissues
D) Pump blood through the body
Answer: C) Exchange materials between blood and tissues
Explanation: Capillaries are tiny blood vessels with thin walls that allow oxygen, nutrients, and waste products to move between the blood and surrounding tissues. This exchange is essential for cellular function.
Respiratory System
The respiratory system brings oxygen into the body and removes carbon dioxide. Every cell needs oxygen to produce energy, and carbon dioxide is a waste product that must be eliminated. Breathing is usually automatic, but you can control it consciously.
Air enters through the nose or mouth and travels down the trachea. The trachea branches into bronchi, which divide into smaller bronchioles. At the end of the bronchioles are tiny air sacs called alveoli where gas exchange occurs.
Oxygen moves from the alveoli into the blood, while carbon dioxide moves from the blood into the alveoli to be exhaled. This exchange happens because gases move from areas of high concentration to areas of low concentration.
The diaphragm is the main breathing muscle. When it contracts, it moves down and expands the chest cavity, drawing air into the lungs. When it relaxes, it moves up and pushes air out of the lungs.
Practice Question:
Where does gas exchange occur in the respiratory system?
A) Trachea
B) Bronchi
C) Bronchioles
D) Alveoli
Answer: D) Alveoli
Explanation: Alveoli are tiny air sacs at the end of the respiratory tree where oxygen and carbon dioxide are exchanged between the air and blood. Their thin walls and large surface area make this exchange very efficient.
Digestive System
The digestive system breaks down food into nutrients the body can use. It also eliminates waste products that the body cannot use. Digestion involves both mechanical breakdown (chewing, churning) and chemical breakdown (enzymes, acid).
Food travels through a long tube from mouth to anus. In the mouth, teeth break food into smaller pieces while saliva begins chemical digestion. The stomach uses acid and enzymes to break down proteins and kills harmful bacteria.
The small intestine is where most digestion and absorption occurs. Enzymes from the pancreas and bile from the liver help break down fats, proteins, and carbohydrates. The intestinal wall absorbs nutrients into the bloodstream.
The large intestine absorbs water from remaining material and forms solid waste. Beneficial bacteria in the large intestine help digest some materials and produce certain vitamins.
Practice Question:
Which organ produces bile to help digest fats?
A) Pancreas
B) Stomach
C) Liver
D) Small intestine
Answer: C) Liver
Explanation: The liver produces bile, which is stored in the gallbladder and released into the small intestine to help break down dietary fats. Bile acts like soap, breaking large fat molecules into smaller droplets that enzymes can digest more easily.
Endocrine System
The endocrine system uses hormones to control body functions. Hormones are chemical messengers that travel through the bloodstream to target organs.
Unlike the nervous system, which acts quickly, the endocrine system produces slower, longer-lasting effects.
Major endocrine glands include the pituitary, thyroid, adrenals, and pancreas. The pituitary gland is often called the “master gland” because it controls other endocrine glands. The hypothalamus in the brain controls the pituitary gland.
Hormone levels are controlled by feedback mechanisms. When hormone levels get too high, the body reduces production. When levels get too low, production increases. This is similar to how a thermostat controls room temperature.
Diabetes is a common endocrine disorder where the pancreas doesn’t produce enough insulin or the body doesn’t respond to insulin properly. Insulin helps cells take up glucose from the blood for energy.
Practice Question:
Which gland is often called the “master gland” of the endocrine system?
A) Thyroid
B) Adrenal
C) Pancreas
D) Pituitary
Answer: D) Pituitary
Explanation: The pituitary gland controls many other endocrine glands by releasing hormones that stimulate or inhibit their function. This coordinating role makes it the “master gland” of the endocrine system.
Urinary System
The urinary system filters waste products from the blood and maintains fluid balance. The kidneys are the main organs that filter blood and produce urine. The bladder stores urine until it’s eliminated from the body.
Each kidney contains about one million filtering units called nephrons. Blood flows through tiny blood vessels in each nephron, where waste products and excess water are removed to form urine. Essential substances like glucose and most proteins are returned to the blood.
The kidneys also help control blood pressure by regulating fluid volume and producing hormones. They maintain the body’s acid-base balance and produce a hormone that stimulates red blood cell production.
When kidney function declines, waste products build up in the blood. This can lead to serious health problems. Some patients need dialysis, which uses a machine to filter their blood when their kidneys can’t do the job.
Practice Question:
What is the functional unit of the kidney called?
A) Alveolus
B) Nephron
C) Neuron
D) Hepatocyte
Answer: B) Nephron
Explanation: The nephron is the basic functional unit of the kidney. Each kidney contains about one million nephrons that filter blood and produce urine by removing waste products while retaining essential substances.
Immune System
The immune system protects the body from disease-causing organisms like bacteria, viruses, and fungi. It has two main parts: innate immunity, which provides immediate but general protection, and adaptive immunity, which provides specific, long-lasting protection.
Innate immunity includes barriers like skin and mucous membranes that prevent pathogens from entering the body. It also includes white blood cells that attack any foreign substance. Inflammation is part of the innate immune response.
Adaptive immunity develops specific responses to particular pathogens. B cells produce antibodies that bind to specific antigens on pathogens.
T cells can directly kill infected cells or coordinate immune responses. Memory cells remember past infections for faster future responses.
Vaccines work by training the adaptive immune system to recognize specific pathogens without causing disease. When exposed to the real pathogen later, memory cells quickly produce antibodies and activate other immune responses.
Practice Question:
Which cells produce antibodies as part of adaptive immunity?
A) T cells
B) B cells
C) Red blood cells
D) Platelets
Answer: B) B cells
Explanation: B cells are lymphocytes that produce antibodies specific to particular antigens. When activated by exposure to an antigen, B cells divide and produce plasma cells that secrete large amounts of antibodies.
Biology
Biology covers the basic principles of life, from molecular processes to whole organisms. Understanding biology helps you understand how the human body works at the cellular level and how traits are passed from parents to children.
Living things share certain characteristics despite their diversity. All living things are made of cells, use energy, grow and develop, respond to their environment, and reproduce. These basic principles apply to humans just as they do to bacteria and plants.
Cell Structure and Function
Cells are the basic units of life. All living things are made of one or more cells. Human cells are eukaryotic, meaning they have a nucleus and other membrane-bound organelles. Bacteria are prokaryotic cells without a nucleus.
The cell membrane controls what enters and leaves the cell. It’s made of a phospholipid bilayer with embedded proteins.
Small molecules like oxygen and carbon dioxide can pass through easily, while larger molecules need special transport proteins.
Major organelles include the nucleus (contains DNA), mitochondria (produce energy), endoplasmic reticulum (makes proteins and lipids), and Golgi apparatus (packages and ships materials). Each organelle has a specific function, like organs in the body.
Cells reproduce by dividing. Mitosis produces two identical cells for growth and repair. Meiosis produces sex cells (sperm and eggs) with half the normal number of chromosomes for reproduction.
Practice Question:
Which organelle is responsible for producing energy in the cell?
A) Nucleus
B) Mitochondria
C) Ribosome
D) Golgi apparatus
Answer: B) Mitochondria
Explanation: Mitochondria are often called the “powerhouses of the cell” because they produce ATP, the main energy currency of cells. They convert glucose and oxygen into ATP through cellular respiration.
Basic Macromolecules
Living things are made of four main types of large molecules called macromolecules. Each type has specific functions that are essential for life. Understanding these molecules helps explain how the body works at the molecular level.
Carbohydrates provide energy and structural support. Simple carbohydrates like glucose provide quick energy. Complex carbohydrates like starch store energy, while cellulose provides structural support in plants.
Proteins have many functions including enzymes, structure, transport, and defense. All proteins are made of amino acids linked together. The sequence of amino acids determines the protein’s shape and function.
Lipids include fats, oils, and cholesterol. They store energy, form cell membranes, and act as signaling molecules. Fats store more energy per gram than carbohydrates, making them efficient energy storage molecules.
Nucleic acids (DNA and RNA) store and transmit genetic information. DNA contains the instructions for making all proteins. RNA helps carry out these instructions and has other important functions in the cell.
Practice Question:
Which macromolecule serves as the primary energy storage in adipose tissue?
A) Carbohydrates
B) Proteins
C) Lipids
D) Nucleic acids
Answer: C) Lipids
Explanation: Adipose tissue stores energy in the form of triglycerides, which are a type of lipid. Lipids provide more than twice as much energy per gram as carbohydrates or proteins, making them efficient for long-term energy storage.
Genetic Material and Protein Synthesis
DNA contains the genetic instructions for all cellular activities. It’s made of four bases (A, T, G, C) arranged in a specific sequence. The sequence of these bases codes for the amino acid sequence in proteins.
Genes are specific sections of DNA that code for particular proteins. Humans have about 20,000 genes spread across 23 pairs of chromosomes. Each cell contains a complete copy of all genetic information.
Protein synthesis involves two main steps: transcription and translation. During transcription, DNA is copied into messenger RNA (mRNA). During translation, ribosomes read the mRNA code and assemble amino acids into proteins.
Mutations are changes in the DNA sequence. Some mutations have no effect, while others can cause diseases or change protein function. Environmental factors like radiation and chemicals can cause mutations.
Practice Question:
During which process is DNA copied into mRNA?
A) Translation
B) Transcription
C) Replication
D) Mutation
Answer: B) Transcription
Explanation: Transcription is the process where genetic information in DNA is copied into messenger RNA (mRNA). This mRNA then carries the genetic code from the nucleus to the ribosomes where proteins are made.
Mendel’s Laws of Heredity
Gregor Mendel discovered the basic principles of inheritance by studying pea plants. His laws explain how traits are passed from parents to offspring through genes.
Each person has two copies of each gene, one from each parent. These different versions are called alleles. Dominant alleles are expressed when present, while recessive alleles are only expressed when no dominant allele is present.
Mendel’s first law states that alleles separate during the formation of sex cells. Each sperm or egg gets only one copy of each gene. When fertilization occurs, the offspring gets one allele from each parent.
Punnett squares help predict the probability of different genetic outcomes. They show all possible combinations of alleles that offspring can inherit from their parents.
Practice Question:
If both parents are heterozygous for a trait (Aa), what percentage of their offspring will show the recessive phenotype?
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B) 25%
Explanation: When both parents are Aa, the Punnett square shows: AA (25%), Aa (50%), and aa (25%). Only the aa genotype shows the recessive phenotype, which occurs in 25% of offspring.
Microorganisms and Disease
Microorganisms include bacteria, viruses, fungi, and parasites. While many microorganisms are harmless or beneficial, some cause diseases. Understanding these pathogens is important for infection control in healthcare.
Bacteria are single-celled organisms that can reproduce independently. Some bacteria cause diseases like strep throat and pneumonia. Antibiotics can kill bacteria but don’t work against viruses.
Viruses are much smaller than bacteria and can only reproduce inside host cells. They cause diseases like the common cold, flu, and AIDS. Antiviral medications can help treat some viral infections.
Fungi include yeasts and molds. Some fungi cause infections like athlete’s foot and yeast infections. Antifungal medications treat these infections.
Disease transmission occurs through various routes including direct contact, droplets, airborne particles, contaminated objects, and vectors like mosquitoes. Understanding transmission helps prevent the spread of infections.
Practice Question:
Which type of medication is effective against bacterial infections but not viral infections?
A) Antivirals
B) Antibiotics
C) Antifungals
D) Antihistamines
Answer: B) Antibiotics
Explanation: Antibiotics specifically target bacterial cell structures and processes that viruses don’t have. Since viruses reproduce inside host cells using the host’s machinery, antibiotics cannot effectively target them.
Chemistry
Chemistry explains how matter behaves and interacts. Understanding basic chemistry helps you understand how medications work, what happens during metabolism, and how the body maintains its chemical balance.
Everything in the universe is made of matter, which consists of atoms and molecules.
Chemical reactions constantly occur in living organisms to maintain life. These reactions follow the same principles whether they happen in a test tube or inside a cell.
Atomic Structure
Atoms are the basic building blocks of all matter. They consist of protons, neutrons, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.
The nucleus contains protons and neutrons and makes up most of the atom’s mass. Electrons orbit the nucleus in energy levels or shells. The number of protons determines what element the atom is.
The periodic table organizes elements by their atomic number (number of protons). Elements in the same column have similar properties because they have the same number of electrons in their outer shell.
Isotopes are atoms of the same element with different numbers of neutrons. Some isotopes are radioactive and break down over time, releasing energy. Radioactive isotopes are used in medical imaging and cancer treatment.
Practice Question:
What determines the identity of an element?
A) Number of neutrons
B) Number of electrons
C) Number of protons
D) Atomic mass
Answer: C) Number of protons
Explanation: The number of protons in an atom’s nucleus determines which element it is. This is called the atomic number. While neutrons and electrons can vary, the number of protons defines the element’s identity.
Chemical Reactions
Chemical reactions occur when atoms or molecules interact to form new substances.
Reactants are the starting materials, and products are the substances formed. Chemical equations show what happens during reactions.
Energy is involved in all chemical reactions. Exothermic reactions release energy, often as heat.
Endothermic reactions absorb energy from their surroundings. Many reactions in living organisms require energy input to proceed.
Catalysts speed up chemical reactions without being consumed. Enzymes are biological catalysts that make reactions occur fast enough to sustain life. Without enzymes, most biochemical reactions would be too slow.
Chemical equilibrium occurs when the forward and reverse reactions happen at the same rate. The concentrations of reactants and products remain constant, but the reactions continue occurring.
Practice Question:
What are biological catalysts that speed up chemical reactions in living organisms called?
A) Hormones
B) Enzymes
C) Antibodies
D) Vitamins
Answer: B) Enzymes
Explanation: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in living organisms. They lower the activation energy needed for reactions to occur, making cellular processes possible at body temperature.
Acids and Bases
Acids and bases are important in biological systems. Acids release hydrogen ions (H+) when dissolved in water, while bases accept hydrogen ions or release hydroxide ions (OH-).
The pH scale measures how acidic or basic a solution is. It ranges from 0 to 14, with 7 being neutral.
Numbers below 7 are acidic, and numbers above 7 are basic. Each unit represents a 10-fold change in acidity.
Strong acids and bases completely ionize in water, while weak acids and bases only partially ionize. Stomach acid is very acidic (pH around 2), while blood is slightly basic (pH around 7.4).
Buffer systems help maintain stable pH in biological fluids. They resist changes in pH when small amounts of acid or base are added. The body has several buffer systems to keep blood pH in the narrow range needed for life.
Practice Question:
What is the normal pH range of human blood?
A) 6.8 – 7.0
B) 7.0 – 7.2
C) 7.35 – 7.45
D) 7.6 – 7.8
Answer: C) 7.35 – 7.45
Explanation: Normal blood pH is tightly regulated between 7.35 and 7.45, making it slightly basic. Values outside this narrow range can be life-threatening, so the body has multiple systems to maintain proper pH balance.
Properties of Solutions
Solutions form when one substance dissolves in another. The substance being dissolved is the solute, and the substance doing the dissolving is the solvent. Water is the most common solvent in biological systems.
Concentration measures how much solute is dissolved in a given amount of solution. Different units express concentration, including molarity, percentage, and parts per million. Understanding concentration is important for medication dosing.
Factors affecting solubility include temperature, pressure, and the chemical nature of the solute and solvent. “Like dissolves like” means that polar substances dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents.
Osmosis is the movement of water across a membrane from an area of low solute concentration to an area of high solute concentration. This process is crucial for maintaining proper fluid balance in cells and tissues.
Practice Question:
What process describes the movement of water across a membrane from low to high solute concentration?
A) Diffusion
B) Active transport C) Osmosis D) Filtration
Answer: C) Osmosis
Explanation: Osmosis specifically refers to the movement of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process is essential for maintaining cellular fluid balance.
States of Matter
Matter exists in three main states: solid, liquid, and gas. The state depends on how much energy the particles have and how strongly they’re attracted to each other.
In solids, particles are tightly packed and vibrate in fixed positions. In liquids, particles are close together but can move around each other. In gases, particles are far apart and move freely.
Phase changes occur when matter changes from one state to another. Melting changes solid to liquid, while evaporation changes liquid to gas. These changes require energy input or release.
Water has unique properties that make it essential for life. It has a high specific heat, meaning it resists temperature changes. It’s also a good solvent for many biological molecules.
Practice Question:
What happens to the energy of particles when a solid melts into a liquid?
A) Energy decreases
B) Energy increases
C) Energy stays the same
D) Energy is not involved
Answer: B) Energy increases
Explanation: When a solid melts, energy must be added to overcome the forces holding particles in fixed positions. This energy allows particles to move more freely, characteristic of the liquid state.
Scientific Reasoning
Scientific reasoning involves using logical thinking and the scientific method to understand the natural world. These skills help you evaluate information, design experiments, and draw valid conclusions from data.
Science is based on evidence and testing ideas through experimentation. Scientific knowledge changes as new evidence becomes available. Understanding scientific reasoning helps you think critically about health information and research findings.
Scientific Method
The scientific method is a systematic way to investigate questions about the natural world. It helps ensure that findings are reliable and can be reproduced by other scientists.
The process begins with observations that lead to questions. Scientists then form hypotheses, which are testable explanations for observations. A good hypothesis makes specific predictions that can be tested.
Experiments are designed to test hypotheses under controlled conditions. Variables are factors that can change during an experiment. The independent variable is what the scientist changes, while the dependent variable is what they measure.
Controls are essential for valid experiments. A control group receives no treatment or a standard treatment for comparison. This helps scientists determine if observed effects are due to the treatment being tested.
Practice Question:
In an experiment testing a new blood pressure medication, what would be the independent variable?
A) The patients’ blood pressure readings
B) The type of medication given
C) The patients’ age
D) The time of day measurements are taken
Answer: B) The type of medication given
Explanation: The independent variable is what the researcher deliberately changes or manipulates. In this case, it’s whether patients receive the new medication, a standard medication, or a placebo. Blood pressure readings would be the dependent variable.
Scientific Measurements
Accurate measurements are essential for scientific investigations. The metric system is used in science because it’s based on powers of 10, making conversions easy.
Basic metric units include meters for length, grams for mass, liters for volume, and degrees Celsius for temperature. Prefixes indicate multiples or fractions of the basic unit.
Precision refers to how close repeated measurements are to each other. Accuracy refers to how close measurements are to the true value. A measurement can be precise but not accurate if there’s a systematic error.
Significant figures indicate the precision of a measurement. When doing calculations, the answer should have no more significant figures than the least precise measurement used.
Practice Question:
How many significant figures are in the measurement 0.00420 grams?
A) 2
B) 3
C) 4
D) 6
Answer: B) 3
Explanation: The significant figures are 4, 2, and 0 (the trailing zero after the 2). Leading zeros before the 4 are not significant – they only show the decimal place. The trailing zero after 2 is significant because it comes after a non-zero digit in a decimal number.
Data Analysis and Interpretation
Scientists collect and analyze data to test their hypotheses. Data can be qualitative (descriptive) or quantitative (numerical). Both types provide valuable information, but quantitative data can be analyzed statistically.
Graphs and charts help visualize data and reveal patterns. Line graphs show changes over time, bar graphs compare different groups, and scatter plots show relationships between variables.
Statistical measures help summarize data. The mean is the average value, the median is the middle value when data is arranged in order, and the mode is the most frequently occurring value.
Correlation describes how two variables are related. Positive correlation means both variables increase together, while negative correlation means one increases as the other decreases. Remember that correlation doesn’t prove causation.
Practice Question:
If a scatter plot shows that as study time increases, test scores also increase, this demonstrates:
A) Negative correlation
B) Positive correlation
C) No correlation
D) Causation
Answer: B) Positive correlation
Explanation: When both variables increase together, this shows positive correlation. However, this correlation alone doesn’t prove that studying causes higher scores – there could be other factors involved.
Logic and Evidence
Scientific thinking requires logical reasoning and careful evaluation of evidence. Not all evidence is equally reliable, and scientists must consider the quality and source of information.
Cause and effect relationships are important in science, but they can be difficult to establish. Just because two things happen together doesn’t mean one causes the other. Multiple factors often influence outcomes.
Bias can affect scientific investigations. Selection bias occurs when samples aren’t representative of the population. Confirmation bias is the tendency to focus on evidence that supports existing beliefs while ignoring contradictory evidence.
Peer review is a process where other scientists evaluate research before it’s published. This helps ensure that methods are sound and conclusions are supported by evidence.
Practice Question:
A study finds that people who carry umbrellas are more likely to get wet. What’s the most likely explanation?
A) Umbrellas cause people to get wet
B) People carry umbrellas when rain is expected
C) Wet people are more likely to buy umbrellas
D) This finding disproves the effectiveness of umbrellas
Answer: B) People carry umbrellas when rain is expected
Explanation: This is an example of correlation without causation. People carry umbrellas when they expect rain, so umbrella-carrying and getting wet are both associated with rainy weather conditions, not a causal relationship between the umbrella and getting wet.
Predicting Relationships
Scientists often need to predict what might happen under different conditions. This requires understanding patterns in data and applying scientific principles to new situations.
Mathematical relationships help describe how variables relate to each other. Linear relationships show a constant rate of change, while exponential relationships show accelerating change.
Models are simplified representations of complex systems. They help scientists understand and predict behavior. Models can be mathematical equations, computer simulations, or physical representations.
Extrapolation means extending a trend beyond the measured data points. This can be useful for making predictions, but it becomes less reliable the further you extend from actual data. Interpolation means estimating values between known data points.
Trends in data help identify patterns that can guide predictions. However, trends can change due to new factors or conditions. Scientists must consider whether current trends will continue under different circumstances.
Practice Question:
A graph shows that a patient’s temperature has increased steadily from 98.6°F to 102.0°F over 4 hours. Using this trend, what would you predict the temperature to be after 6 hours?
A) Exactly 103.7°F
B) Approximately 103.7°F, but this assumes the trend continues
C) The temperature will definitely keep rising
D) The prediction is impossible to make
Answer: B) Approximately 103.7°F, but this assumes the trend continues
Explanation: Mathematical extrapolation suggests 103.7°F, but medical knowledge tells us that body temperature trends don’t continue indefinitely. The patient’s condition, treatment, or natural fever patterns could change the trend. Good scientific prediction acknowledges both the mathematical projection and its limitations.
Common Question Types and Strategies
Anatomy and Physiology Questions: Often ask about normal function or what happens when things go wrong. Think about cause and effect relationships. Consider how different body systems work together.
Example Strategy: If a question asks what happens when blood pressure drops, think about which systems respond (nervous system increases heart rate, kidneys retain fluid, blood vessels constrict).
Biology Questions: Frequently test your understanding of cellular processes and genetics. Remember that structure determines function at every level from molecules to organisms.
Example Strategy: For genetics problems, draw out Punnett squares if needed. Remember that dominant alleles mask recessive ones, and each parent contributes one allele for each trait.
Chemistry Questions: Often relate to processes happening in the body. Think about pH, concentration, and chemical reactions in biological systems.
Example Strategy: For pH questions, remember that blood must stay slightly basic (pH 7.35-7.45). Consider what happens when this balance is disturbed.
Scientific Reasoning Questions: Test your ability to analyze experiments and interpret data. Focus on identifying variables, controls, and valid conclusions.
Example Strategy: For experimental design questions, identify what’s being tested (independent variable) and what’s being measured (dependent variable). Look for proper controls.
Avoiding Common Mistakes
Don’t overthink questions. The TEAS tests basic concepts, not advanced details. If you find yourself thinking about rare exceptions or complex mechanisms, step back and consider simpler explanations.
Watch for absolute words like “always,” “never,” “all,” and “none.” In biology and medicine, few things are absolute. Answers with these words are often incorrect.
Be careful with similar-sounding terms. Many anatomy terms sound alike but have different meanings. Make sure you understand the difference between terms like “superior/inferior” and “anterior/posterior.”
Don’t let one difficult question ruin your confidence. If you’re struggling with a question, remind yourself that only 44 questions count toward your score. You can miss a few questions and still get a good score.